Using MiniProfiler with Angular & HttpClient for SPAs http://www.arturdr.ru/net/using-mini-profiler-with-angular-and-httpclient/ (ported from https://gist.github.com/GeorgDangl/2807d11b367540e1de5629502289f5a8)

app.module.ts

import { NgModule } from '@angular/core';
import { HttpClientModule, HTTP_INTERCEPTORS, } from '@angular/common/http';
import { MiniProfilerInterceptor } from './mini-profiler-http';

@NgModule({
    providers: [
        { provide: HTTP_INTERCEPTORS, useClass: MiniProfilerInterceptor, multi: true },
    ]
})
export class AppModule { }

MiniProfilerInterceptor.ts

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpHandler, HttpRequest, HttpEvent, HttpResponse, HttpHeaders }
  from '@angular/common/http';

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/do';
declare var MiniProfiler: any;

@Injectable()
export class MiniProfilerInterceptor implements HttpInterceptor {
  intercept(
    req: HttpRequest<any>,
    next: HttpHandler
  ): Observable<HttpEvent<any>> {

    return next.handle(req).do(evt => {
      if (evt instanceof HttpResponse) {
        if (typeof MiniProfiler !== 'undefined' && evt && evt.headers) {
          this.makeMiniProfilerRequests(evt.headers);
        }
      }
    });
  }

  private makeMiniProfilerRequests(headers: HttpHeaders) {
    const miniProfilerHeaders = headers.getAll('x-miniprofiler-ids');

    if (!miniProfilerHeaders) {
      return;
    }

    miniProfilerHeaders.forEach(miniProfilerIdHeaderValue => {
      const ids = JSON.parse(miniProfilerIdHeaderValue) as string[];
      MiniProfiler.fetchResults(ids);
    });
  }
}